Flat computer display panels (see FIGS. 1a-1c) require attachment of two glass substrates 6 and 8. One substrate 6 contains an active device area 10 of thin film transistors (also referred to as TFT's) and accompanying circuitry. Second substrate 8 comprises a color filter 11. About the edges of color filter 11 there is a peripheral region 12 consisting of a layer of chrome oxide 14 over which there is deposited a layer of chrome 16. In some cases, peripheral region 12 consists of an organic resin. In both cases, these layers are referred to as black matrix 17.
A sealant 18 is applied just prior to attachment of substrates 6 and 8. Circuitized substrate 6 is placed over sealant 18 which results in a major fraction of sealant 18 spreading into the black matrix region. Curing of sealant 18 generally requires the use of uv light, in the range of 350-360 nm in wavelength (although certain sealants respond to different wavelengths, they are not generally used for flat display panels). The incident uv light stimulates certain initiators in sealant 18 that cause a reaction leading to cure or cross linking therein, resulting in a leak-tight seal.
However, there is a curing problem in parts of this sealant region where there is metallization 22. Metallization 22 comprises data and gate lines of the TFT substrate that extend out from the sealed region for connection to driving electronic circuitry. In metallized regions located above sealant 18, the uv light is shadowed and sealant 18 beneath the shadowing metallization tends to remain uncured.
Accordingly, it is an object of the invention to provide an improved method for affixing two objects together with a curable sealant.
It is a further object of the invention to provide a method and system for curing a sealant that is shadowed by metallization components.